Pressure cooker cover fastener



July 8, 1947.

PRESSURE COOKER COVER FS TENER Filed July 27, 1946 2 Sheets-,Sheet l BY y 'om 0%.M M

J. L. HVALE 2,423,559I

July 8, 1947. J. L. HVALE 2,423,559

PRESSURE COOKER COVER FASTEER 'Filed July 27, 194e 2 sheets-sheet 2 Patented July 8, 1947 2,423,559 PRESSURE cooKER COVER FAs'rENER James L. Hvale, Chicago, Ill., assignor to Ekco Products Company, Chicago, Ill., a corporation of Illinois Application July 27, 1946, Serial No. 686,623 (C1. 2go- 55) Claims. 1

The invention relates generally to pressure cookers of a type suitable for home use, and more particularly to the cover structure of such a cooker.

The general object of the invention is to provide a pressure cooker of the type having an elliptical opening and cover with the cover removable from and insertable into the receptacle by tilting the cover and rotating it 90 out of alignment with the opening, the cooker having novel means for effectively moving the cover into tight sealing engagement with the underside of the margin of the opening so that pressure may be built up within the receptacle.

Another object is to provide a novel pressure cooker of the foregoing type, in which the cover is primarily urged by a Spring into sealing enthrough manually operable means.

A further object is to provide a novel pressure cooker of the foregoing type, having a manually rotatable element to turn the cover into and out of alignment with the receptacle opening and a spring for effecting primary sealing engagement of the cover with the margin of the opening, said manually rotatable element being adapted, by rotation beyond What is necessary to align the cover with the opening, to tighten such engagement.

Still another object is to provide a pressure cooker of the foregoing type, having a spring tending to move the cover into sealing engagement with the margin of the opening, and a manually rotatable member for turning the cover into and out of alignment with the opening, the turning movement of said member in a direction to move the cover out of such alignment providing a locking action holding the cover against movement by the spring, and turning movement in the opposite direction releasing the lock to permit 4the spring to act and, with continued turning movement, to force the cover into tighter engagement with the margin of the opening than that effected by the spring alone'.

Other objects and advantages will become apparent from the following description taken in connection with the accompanying drawings, in which:

Figure 1 is a fragmentary sectional view of a pressure cooker showing the manner in which the cover engages the receptacle.

Fig. 2 is a plan View of the pressure cooker shown in Fig. 1 and illustrating the cover in a position ready for removal.

Fig. 3-is a fragmentary plan View, partially in section, of the cover supporting means, the sectional portion thereof being taken on the line 3--3 of Fig. 4, and showing the parts in position for removal of the cover.

Fig. 4 is a vertical sectional view taken on the line 4-4 of Fig. 3. l

Fig. 5 is a view similar to Fig. 3 but showing the parts in their position when the cover is initially clamped in sealingengagement with the receptacle.

Fig. 6 is a vertical sectional view similar to Fig, 4 but taken on the line 6-6, of Fig. 5.

Fig. 7 is a view similar to Figs. 3 and 5 but showing the position of the parts when the cover is fully clamped in sealing engagement with the receptacle. Y

Fig. 8 is a vertical sectional view similar to Figs. 4 and 6 but taken on the line 8-8 of Fig. '7.

The novel features of the invention disclosed herein, while relating generally to a pressure cooker, refer particularly to the means for clamping thecover to the receptacle so that a, tight seal Y is Yeffected therebetween and steam pressure may be raised within the receptacle. To illustrate the invention, I have shown in Figs, 1 and 2 a receptacle I0 which is of generally cylindrical form with the side wall bent inwardly at its upper edge to provide a ange II. 'The flange II defines an opening I2 adapted to be closed by a cover I3. Theilange II and cover I3 are so arranged thatrthe cover extends under the angeto engage the underside thereof sol that steam pressure within the receptacle I0 will tend to cause the cover to move into tight clamping engagement with the flange Il. Thusthe construction may be said to be in some respects self-sealing. ,In the present instance, the cover I3 is provided with an outwardly directed ange I4 at its periphery with a gasket I5 of rubber or the like seated and rigidly secured in the flange I4 to engage the flangeY I I when the cover is clamped in position.

In this type of construction, the opening I2, as Well as the cover I3is preferably made elliptical or oval inform, and the cover, when it is to be removed, is rotated out of alignment with the opening I2, as illustrated in Fig; 2, so that the shorter diameter of the cover can be passed through thelonger diameter of the opening I2. To permitsuch passage, the lcover I 3 is tilted and one edge at the extremity of the longer diameter is passed4 through the opening and the entire cover thereby removed. VThis generalc'onstrue-` tionjoi theicover and theopeningwhich it closes is well known in they art. Y Y Y Y receptacle.

As mentioned above, the invention herein relates to the means for supporting and manipulating the cover I3 so that it may be readily removed from the receptacle and may be re-inserted therein and forced into tight clamping engagement with the flange II of the receptacle. The cover supporting means comprises generally a bridge member adapted to rest on the receptacle and to rotatably support the cover in its movement in vand out of alignment with the opening I 2 and to provide for movement of the cover vertically relative to the receptacle. The cover is preferably supported on a stem normally secured to a manually rotatable member by which the cover may be turned relative to the bridge member and relative to the receptacle, When the cover is rotated out of alignment with the opening I2, it is locked and held out of engagement with the flange II. When rotated back into alignment with the opening I2, spring means is provided for primarily moving the -cover into sealing engagement with 'the Vflange II, and then "further rotation of the manually operable member is permit* ted to effect a tightening ofthe cover against the flange II without furtherrotation ofthe cover;

In the particular embodimentillustrated in the drawings, I have shown a bridge member 2i! of generally channel-shaped cross section and upwardly bentintermediate its ends so that said ends may rest in pockets 2l provided on the receptacle preferably in handle portions22 of the The bridge memberZ thusfspans the opening I2 and is held against rotation. relative to the receptacle. At its mid point, the bridge ZIJ is provided Vwith an aperture through which a stemy 23 extends, the stem being provided at its lower end with a reduced threaded portion 24 to receive the cover I3 and a nut 25 to clamp the cover on 4the stem,

The stem 23 is adaptejdto be rotated' to move the cover into and out of .alignment with the opening I2 and to move vertically relative to the bridge member 2l) toshift the cover into and out of vsealingengagement wth the rim II of thel receptacle.

'Ifo this end, I provide a manually rotatable member, herein shown in the form of aninverted cup 2t, preferably of plastic material andcmountedover a metallic Vcup 27, the two cups being rigid with vone another. 'The Vcup 2l is frictionally connected to the'st'em ZS/by means hereinafter described Vwhich permits the manually rotatable member'Z to be rotated with the cover to swing the cover into and out of alignment with the opening I2, but permits rotationof the member vZrelative to thecover to eie'ct the tightening of the Asealing engagement of the cover with the flange] I.

When the cover is rotated out of alignment with the opening I2, as illustrated in Fig. V2, I provide means for holding the cover'so that it is out of engagement with the flange II. In the present instance, such means comprises a cupf slit portion thereof. The upper edge of the lug 33 engages the shoulder 32 to hold the manually rotatable member 26 down. Thus, the cover I3 will be held at a point remote from the bridge member, that is, spaced a substantial distance below the bridge member so that the ange I4 of the cover is out of engagement with the ange I I of the receptacle. A coiled spring 34 mounted within the cup-shaped element 30 about the stem .23 and bearing against the bottom of the cupshaped element Sil exerts an upward pressure tendingto ,move the manually rotatable member 2 5 upwardso that the lug 33 is held in tight engagement with the shoulder 32.

rIhe shoulder 32 extends for 90 about the cupshaped element 3l) so that the cover may be rotatedthrough a angle into and out of alignment with the opening I2 while its periphery is out of engagement with the flange II. Thus, as shown in Fig. 3, the lug 33 engages oneV end of the shoulder 'g'whileV the other end of the shoulder tlzlemerges into a vertical channel 35 formed in the side of the cup-shaped-element 3B. When the manually rotatable member 2B is rotated 90 counterclockwise `from the positionvshown in Fig. 3, the lug 33 becomes aligned wit-hthe channel 35 to permit the manuallyrotatable member to be moved upwardly under the influence of Vthe spring 3. Such upward movement of-the-man ually-rotatable member'ZIi,` of course, carries the cover I3 Ywith it since-it is connected thereto by means of the stem 23, Vand the iange I4 on the cover thereby primarily engages the flange II of the receptacle for sealing engagement.V

It is found practice that the sealing engagement eiiected a spring, such as the springll, even with the help of pressure withinthe Vessel, is not sufcient to hold'the pressure within the vessel. Frequently, thiiszis due to aslight springing or `warping ofthe cover whichmay loccurin the manufacture thereof or may arise asa result of mishandiing duiing'use. The present structure provides means Yfor increasing `the pressure or tightening lthe sealing engagement to an extent sufficient to guarantee that pressure will beretained within the receptacle. 'Since rotation of the manually Arotatable member 2651s utilized ,to bring the coverintoV alignment withthe opening Y l2 and the spring automatically causes the cover to engage theV flange VIl when the cover'is'in such alignment, `it is desirable that continuedrotation of the manually rotatable ymember j2i3 be utilized to effect the tighteningo'the sealing engagement. However, for suchcontinuedrotation of themanually rotatable membenthe cover must be released therefrom so that it will not turnbeyond its point of alignment. To this end, I provide a frictional connectibn between the manually rotatable member lili and the stem '21,3 which offers a torque resistance smaller `thanA thetorque resistance ojiiered by the` irictionrbetween the periphery of,y the cover andJthe ange I I Yof the receptacle. Thus, when the cover It is caused-to engage the nange Il ,by kthe action of the spring 3d, the frictional connectionbetween the manually rotatable member 26 andthe stem .23.yields and permits relative lrotation therebetween, and such further rotation of the manually rotatable member may then be utilized .to effect further tightening of thecover. l Y

The frictional connection herein shown comprises a plurality of lbaar-ing members carried by the manually rotatable member Zit-and a pressure Y member held in engagement with the bearing members by the spring '34, `In the specific form illustrated, I provide a disc 40 having a flange portion 4I extending through an aperture in the metallic cup 2I and crimped thereto so that the disc 40 is rigidly connected to the metallic cup 2'I for rotation therewith. The disc 40 is also utilized to secure the manually rotatable member 23 in place by being provided with a central, threaded aperture to receive a screw 42 clamping the manually rotatable member 25 on the metallic cup 2l.

The disc 43 serves as a carrier for a plurality of bearing members comprising, in the present instance, three downwardly extending pins 43 having rounded heads 44. The rounded heads 44 are adapted to engage a disc 45 keyed to the stem 23 but movable longitudinally thereof. The dise 45 serves as an upper bearing plate for the spring 34 so that the latter holds the disc 45 in frictional engagement with the rounded heads 44 of the pins 43. The disc 45 is provided with depressions 43 in which the heads 44 are normally seated during the rotative movement of the cover I3.

Thus, during ino-vement of the cover into and out of alignment with the aperture I2 of the receptacle, the frictional engagement between the pins 43 and the disc i5 provides a driving connection between the manually rotatable member 25 and the cover I3. However, when the cover has been moved into engagement with the flange I I by the spring 34 and the torque resistance of such engagement is encountered, rotation of the manually rotatable member 26 causes the heads lili of the pins to cam out of the depressions 45 and force the disc 45 downwardly on the stem a slight distance against the pressure of the spring 33. The manually rotatable member 25,v therefore, may be rotated at such time without rotating the cover I3.

'Io eifect a tightening of the sealing engagement of the cover with the flange I I, such further rotation of the manually rotatable member 25 is utilized by providing coacting means on the cupshaped member 35 and the manually rotatable member 26. Thus, I provide a lug 55, formed by slitting and indenting the metallic cup 2l, at a point diametrically opposite the lug 33, the two lugs being positioned so'that their bottom edges are on the same level. The lug 55 is adapted to move vertically in a channel 5I in the cup-shaped member 30 when the spring acts to move the cover upwardly. However, when the spring has moved the cover into engagement with the ange II, which is the position shown in Figs. 5 and 6, the lower edges of the lugs 33 and 50 may be turned into engagement with the upper edge of the cupshaped element 35. To produce the tightening action, the upper edge of the cupi-shaped member 30 is provided with a pair of upwardly slanting cam surfaces 52 engageable by the lugs 33 and 55 so that, with the further rotation of the manually rotatable member 23, the latter is forced upwardly to draw the cover in tighter engagement with the flange II of the receptacle. rhus, rotation of the manually operable member 25 is utilized to effect the tightening of the sealing engagement of the cover with the receptacle.

When it is desired to remove the cover, the manually rotatable member 25 is reversely rotated, permitting the lugs 33 and 58 to move downwardly along the cam surfaces 52, thus partially Vloosening the sealing engagement. When the lugs 33 and 50 have moved into registry with the channels 35 and 5I, the cover may be forced downwardly by pressure on the manuallyrotatable member 26 to comp-ress the spring34. When the lug 33k reaches the level of the locking shoulder 32, rotation of the manually rotatable member causes engagement of the lug 33 with the shoulder 32 and also rotates the cover out of alignment with the opening. In order to insure that there will be no slippage of the frictional connection .between the manually rotatable member 26 and the cover I3 during the rotation to effect the locking, I provide a third disc or washer 53 interposed between the discs 4G and 45 and rigidly connected to the upper end of the stem 23. The intermediate disc 53 is provided with ar cuate slots 54 through which pins 43 extend. When the manually rotatable member 25 is ready to rotate the lug 33 into locking engagement with the shoulder 32, the pins 43 are at one end of the arcuate slots 54 so that rotation of the cover I3 with the manually rotatable member 26 at that time is thereby insured. The slots have an arcuate length suicient to permit the lugs 33 and 50 to move upwardly on the cam surfaces 52 so that during such period the manually rotatable member 26 is freed of the stem 23.

To briefly describe the operation, let us assume that the parts are in the position shown in Fig. 2 where the cover I3 is 90 out of alignment with the opening I2. At such position, the lug 33 is in engagement with the locking shoulder 32 at the opposite extremity thereof from the channel 35, as shown in Figs. 3 and 4. By counterclock wise rotation of the manually rotatable member 25 from such position, the lug 33 is brought in registry with the channel 35 and the cover I3 is brought into alignment with the opening I2. The spring 35i thereupon moves the cover upwardly to engage the ange il of the receptacle in primary sealing engagement.

' Further counterclockwise rotation of the man.. ually rotatable member 25 effects release of the frictional engagement between the pins 43 and the disc 45 since the torque resistance of the cover I3 with the flange II exceeds the torque resistance between the pins i3 and the disc t5. At such time, the lugs 33 and 53 are'at the start of the inclined cam surfaces 52 so that such `further counterclockwise rotation of the manually rotatable member 26 exerts a further upward pressure of the cover I3 against the flange I i. A slight flexing of the cover may take place at this time. Such further rotation is permitted since the pins may, during this period, move in the arcuate slots 53.

On clockwise rotation of the manually rotatable member 26 to open the receptacle, the pins again slide on the disc 45 until they reach the point where they are seated in the depressions 45 therein. At that point, the pins 53 have reached the ends of the slots 54, and the lugs 33 and 53 have moved into. registry with the channels 35 and 5I. The manually rotatable member 2S is then pressed downwardly to compress the spring 34 and, by further counterclockwise rotation, the lug v33 is moved into engagement rwith the locking shoulder 32 to hold the cover at a point below or spaced from the flange Ii. Continued rotation in the counterclockwise direction moves the cover out of alignment with the opening I2 so that it may be tilted and removed.

From the foregoing description, it will be apparent that I have provided novel means for moving a cover of the type herein disclosed into tight sealing engagement with the margin of the opening of the receptacle. While the spring 34 primarily acts to effect the sealing engagement, tightening thereof is effected throughcontinued rotation of the manually rotatable member 25 7 after therotation thereof` which-moves the cover into alignment with the opening I2; When the cover is in position for removal, itpis held bya locking action against engagement with Ythe flange Il so that it may be readily tilted and removed from the receptacle I claim:

l. In a pressure cooker comprising a'receptacle having an elliptical top opening and a cover with the cove-r engageable with the underside of the margin of said opening and movable therethrough when tilted and rotated 90 out of alignment with the opening, means for effecting rotation of the cover into alignment with theopening and movement thereof upwardly into sealing engagement with said margin, said means comprising a vertical stem projecting from the cover, a'bridge member adapted to rest on theV receptacle land rotatably-- and slidaibly supporting said ste-m, a locking element Xedto said bridgelmember, a manually rotatable element connected .to said stem for rotating said-cover relative to said bridge -member and adapted by rotation in. one direction to move into locking engagement with saidlocking element to hold the cover in a remote position from said ,bridge member, spring means Y adapted to move said cover toward said bridge member and into engagement with the margin of said opening when said rotatable element isout of locking engagement Withzsaid locking element, and means connecting said manually rotatable element with said stem permitting rotation of the former independently of the latter when the cover engages said margin, said rotatable element cooperating with said locking element to effect further upward movement of the cover when said rotatable element is vrotated independently of the stem.

2. In a pressure cooker comprising a receptacle having an eliptieal top opening and a cover with the cover engageable with the underside of the margin of said opening and insertable theretlnough when tilted and rotated 90 out of alignment with the opening, means for effecting rotation of the cover into and out of alignment with the opening and movement thereof upwardly into sealing engagement with said margin when alignedwith said cover, said means comprising'a bridge mem-ber adapted to rest on the-receptacle and supporting said cover for rotation and vertical movement relative thereto, a locking element Xed to said bridge member, a manually rotatable element connected to said'cover for rotating said cover relative to said bridge member and adapted by rotation in one direction to move into locking engagement with said locking element to hold the cover in a remote position from said bridge member, spring means adaptedto move said cover toward said bridge member and into engagement with the margin of said opening when said elements are out of locking engagement with each other, and means connecting said manually rotatable element with said cover permitting rotation of the former independently of the latter when the cover engages said margin, said rotatable element cooperating with said locking element to eiiect further upward movement of the cover when said rotatable element is rotated independently of the cover.

3. In a pressure cooker comprising a recepta-V ole having an elliptical top opening and a cover with the cover engageable with the underside of the margin of said opening and insertabletherethrough when tilted and rotated 90 out of-alignment with the openingmeans for effecting rotation'o'f the .cover intoalignment with the opening andimovement ythereof upwardly into sealing engagement with said margin, said means comprisingrmeans adapted to engage the receptacle and supporting said cover for rotation and vertical movement relative thereto, a manually rotatable element connected to said cover for r0- tating saidcover and adapted by rotation in one direction to move into locking engagement with saidreceptacle engaging means to hold the cover ina-remote position from the latter means, spring means adapted to move said cover toward the latter means and into engagement with the margin o1" said opening when said element is free of said locking engagement, and means connecting said ele-ment with said cover permitting rotation of the former independently of the latter when the cover lengages said margin, said element cooperating with saidreceptacle engaging meanslto effect `further upward movement of the cover when said element is' rotated independently of the cover,

fi. A pressure cooker comprising a receptacle having an elliptical top opening, a cover engageable with the underside of the margin of said opening and insel-table therethrough when tilted and rotated out of alignment with the opening, means adaptedto engage the receptacle and supporting the cover for rotation and vertical mover relative to the receptacle, Va manually .ble element carrying said cover yand normaliy rotatable with` said cover, said element being adapted ley-rotation in one direction to rotate said cover out of alignment with the opening and to engage said means in locking relation to hold the cover in a remote position from said means, and by rotation in the opposite direction to rotate said cover into alignment with said opening and to bedisengaged `from locking relation with said and a spring for moving said cover into engagement with the margin of said opening when said element is disengaged from locking relation with said means, said element being rotatable relative to said cover when the latter engages said margin and cooperating with said means to effect further upward movement of the cover.

5. In a'pressure cooker comprising a receptacle having an elliptical top opening and a cover with the cover engageable with the underside of the margin of said opening and insertable therethrough when'tilted and rotated 90 out of alignment with the opening, means for eiecting rotation of the cover into alignment with the opening and movementY thereof upwardly into sealing engagement with said margin, said means comprising a bridge member adapted to rest on the receptacle and supporting said cover for rotation and vertical movement relative thereto, a locking `element xed to said bridge member, Ya manually rotatable element connected to said cover for rotating said cover relative to said bridge member 4and adapted by rotation in one direction to move into locldng engagement with said locking element to hold the cover in a remote position from said bridge member, spring means adapted Vto move said Ycover toward said bridge member and into engagement with the margin of said opening when said elements vare out of locking engagement with each other, and means frictionally Vconnecting said manually rotatable element .with said cover and having less frictional resistance than-the frictional engagement of said cover with said marginto permit rotation of said manually rotatable Velement relative'to 'said cover when said cover engages said margin,

said elements having cooperating cam portions to effect further upward movement of the cover when said rotatable element is rotated relative to said cover.

6. In a pressure cooker comprising a receptacle having an elliptical top opening and a cover with the cover engageable with the underside of vthe margin of said opening and insertable therethrough when tilted and rotated 90 out of alignment with the opening, means for elfectng rotation of the cover into alignment with the open- .ing and movement thereof upwardly into sealing engagement with said margin, said means comprising a bridge member adapted to rest on the receptacle and supporting said cover for rotation and vertical movement relative thereto, a fixed element mounted on said bridge member and having a locking surface and a cam surface, a manually rotatable element connected to said cover for rotating said cover relative to said bridge member and having a pair of lugs respectively engageable with said surfaces on said fixed element, said manually rotatable element being adapted by rotation in one direction to move one of said lugs into locking engagement with said locking surface to hold the cover in a remote position from said bridge member, a, spring adapted to move said cover toward said bridge member and into engagement with the margin of said opening when said one lug is out of engagement with said locking surface, and means connecting said manually rotatable element with said cover permitting rotation of the former independently of the latter when the cover engagesl said margin, the other of said lugs engaging said cam surface to effect further upward movement of the cover when said manually rotatable element is rotated independently of the cover.

7. In a pressure cooker comprising a receptacle having an elliptical top opening and a cover with the cover engageable with the underside of the margin of said opening and movable therethrough when tilted and rotated 90 out of alignment with the opening, means for elTecting rotation of the cover into alignment with the opening and movement thereof upwardly into sealing engagement with said margin, said means comprising a vertical stem projecting from the cover, a bridge member adapted to rest on the receptacle and rotatably and slidably supporting said stem, a cup-shaped locking element fixed to said bridge member and having a locking surface in its side and a cam surface on its upper edge, a cup-shaped manually rotatable member telescoping over said locking element and connected to said Stem for rotating said cover relative to said bridge member and having a pair of lugs engageable with said surfaces, said manually rotatable member being adapted by rotation in one direction to move one of said lugs into engagement with said locking surface to hold the cover ina lowered position relative to the bridge member, a spring surrounding said stem within said elements and adapted to raise said cover toward said bridge member and into engagement with the margin of said opening when said one lug is released from said locking surface, and means connecting said manually rotatable element with said stem permitting rotation of the former independently of the latter when the cover engages said margin, the other of said lugs engaging said cam surface to effect further upward movement of the cover when said manually rotatable element is rotated independently of the stem.

Cil

8. In a' pressure cooker comprising a receptacle the cover engageable with the underside of the margin of said opening and movable therethrough when tilted and rotated out of alignment with the opening, means for effecting rotation of the cover into alignment with the opening and movement thereof upwardly into sealing engagement with said margin, said means comprising a vertical stem projecting from the cover, a bridge member adapted to rest on the receptacle and rotatably and slidably supporting said stem, a locking element xed to said bridge member, a manually rotatable element connected to said stem for rotating said cover relative to said bridge member and adapted by rotation in one direction to move into locking engagement with said locking element to hold the cover in a remote position from said bridge member, a coiled spring surrounding said stem and adapted to move said cover toward said bridge member and into engagement with the margin of said opening when said rotatable element is out of locking engagement with said locking element, and means connecting said manually rotatable element with said stem permitting rotation of the former independently of the latter when the cover engages said margin, said connecting means comprising a pair of discs rotatable respectively with said manually rotatable element and said stem, one of said discs carrying a plurality of spherical head pins and the other disc having a plurality of depressions to receive said spherical heads, and said spring tending to hold said heads in said depressions to cause rotation of the two discs together, said r0- tatable element cooperating with said locking element to eifect further upward movement of the cover when said discs are rotated relative to each other.

9. In a pressure cooker comprising a receptacle having an elliptical top opening and a cover with the cover engageable with the underside of the margin of said opening and movable therethrough when tilted and rotated 90 out of alignment with the opening, means for effecting rotation of the cover into alignment with the opening and movement thereof upwardly into sealing engagement with said margin, said means comprising a vertical stem projecting from the cover, a bridge member adapted to rest on the receptacle and rotatably and slidably supporting said stem, a locking element xed to said bridge member, a manually rotatable element connected to said stem for rotating said cover relative to said bridge member and adapted by rotation in one direction to move into locking engagement with said locking element to hold the cover in a remote position from said bridge member, a coiled spring surrounding said stem and adapted to move said cover toward said bridge member and into engagement with the margin of said opening when said rotatable element is out of locking engagement with said locking element, and means connecting said manually rotatable element with said stem permitting rotation of the former independently of the latter when the cover engages said margin, said connecting means comprising a pair of discs rotatable respectively with said manually rotatable element and said stem, one of said discs carrying a plurality of pins held in frictional engagement with the other disc by said spring to cause rotation of the discs together, said rotatable element cooperating with said locking element to effect further upward movement of the cover when the frictional resistance of the cover against tnerethrougnvvhen tilted andSrotateclfQOFI out of 10l alignmentiwith-.the opening; means-for eiecting rotation fof; the' cover; intopand out of alignment With-lthe-opening andmovement thereofupwardly into sealing engagement with said margin when alignedwith said cover, said means comprising abridgemembertadaptedgto rest on the receptacle andisuportingl said.; coverffor. rotation and vertical' movement. relativey thereto; a manually frotat- 12 able velement iconnectedto ysaidcover iforrotating the cover: relative to. said bridge4 member and adapted byf-such"rotationV to move thecover into and out of alignment with said opening, spring means adapted to move said cover'toward said bridge member and intoengagementvvitnthe marginloffsaidopening 'when' .the cover isv in .align-` ment Iwith said opening, `means connectingfsaid manually rotatable element with said cover'permitting rotation of the former iifidependentlir of thev` latterl when the f covert-engages said l margin, and'` anvelement xedlto said bridge member'and cooperating with said manually rotatable element, When thelatteris rotatedindependently of the cover; to eiect'further upward movement of the cover.

JAMES L. 

